How to Do Energy Storage on a Massive Scale

Danielle Fong is not one to make things easy for herself. At 12, she dropped out of middle school and... went to college. After finishing up at Dalhousie University, she enrolled in a Princeton PhD program at 17, where she wanted to work on perhaps the world's most perplexing energy technology: nuclear fusion. Finding that wanting, she went looking for a new challenge and ended up co-founding LightSail Energy.

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LightSail makes what sounds like the world's least sexy product: a new kind of air compressor. But compressed air could be the key to storing electricity on the very large scale required by utilities. And that, as it turns out, would be a key advance in creating a new energy system based on intermittent sources like wind and solar.

I saw the LightSail prototype in their old offices in an old fire station in Oakland's Chinatown. (They've since moved on to a larger space, a former chocolate factory in Berkeley.) There's not much to differentiate it from any other piece of industrial equipment, but few makers of traditional air compressors get backing from Khosla Ventures and TriplePoint Capital.

Previous compressed air systems lost the vast majority of power that you could put into them. But LightSail says their system can return 70 percent of the power that's put into it back to the grid. That'd be as effective as the current best solution (literally pumping water up a hill, then releasing it back through turbines) but with less restrictions. The key to their technology is the simple addition of a fine mist of water during the compressor's operation; the key to their business is proving that their technology works the way they say it does.

Stay tuned for the next two segments of my interview with Fong, which will debut next week.

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